To develop my game to the point where I reach final tables in low stakes tournaments (20$ buyin or below) on a regular basis that exceeds the probability of winning an online poker tournament.

To start winning enough money to pay for vacations and buyins to larger tournaments.

To be able to buy a really cool car (for some reason I get the urge to play poker whenever I see a sweet looking car pass me on the street).

The fact that the game changes nature throughout the tournament and that you have to adapt to these changes.

The chance of winning big with a small initial investments.

The feeling of accomplishment when you reach a final table having beaten a large field of players.

The feeling of accomplishment when you outplay an opponent.

The fact that playing tournaments can be seen as stand-alone events with an upper time limit as compared to grinding SNGs or cash game tables which are ongoing events without time limits. IMO this makes tournament play less obligating.